Approximately fifteen years ago, Dr. Oonagh Mullarkey was employed at the HELL facility, under the alias Ms. Tieque. She collected genetic samples from six inmates from the McCloud Penal Institute for the Criminally Insane, and gene spliced it into several research subjects, presumably some sort of monkeys. The creatures developed into powerful and intelligent, semi-humanoid forms, some with violent tendencies. The most intelligent and most violent of the group, the subject designated Number One, eventually broke out. Using a dimensional warp ability it developed, it took several of the other subjects with it and escaped. Number One became Prime Evil (taking the name from the prime number one), and the other subjects became his Pride (like a pack of lions). They relocated to the Savage Land, where Prime Evil built a laboratory, where they hoped to create and control a powerful race of genetically engineered creatures to control the world.
In the modern era, Prime Evil's Pride began pursuing random attacks throughout both Canada and the UK. They also located Dr. Mullarkey, who now working for Gena-Sys, a division of Mys-Tech, in London, England. They abducted Mullarkey and brought her to the Savage Land to force her to assist their efforts to create a race of warriors. Mullarkey's trail was followed by the group Genetix (who were more recent products of her experiments) and the mutant Wolverine (who had tracked them from their slayings in Canada). Prime Evil and the Pride captured Wolverine and several members of Genetix. He forced Mullarkey to take samples from Wolverine, and to splice the samples with dinosaurs, creating the warrior race he had sought. In addition, he had control bands placed on the Genetix members Ridge and Stinger to control them. He then sent Ridge, Stinger, his Pride, and the Dino Men to attack the other three members of Genetix, who had been joined by Ka-Zar, Zabu, and some warriors of the Fall People.
However, Mullarkey had designed the Dino Men so that they were extremely unstable, and they literally fell apart after a short battle with the heroes. While Prime Evil was watching the battle, she freed Wolverine. The other heroes defeated the members of the Pride, freed Base and Stinger from Prime Evil's control, and converged on his citadel. Mullarkey's superior, Wychwood, led a group of Mys-Tech agents to the Savage Land, where they neutralized the force field around the citadel. The Mys-Tech agents opened fire on the citadel, causing it to collapse.
Prime Evil and the heroes all escaped the collapsing citadel, but in the course of their final battle, Prime Evil's genetic structure began to destabilize as well. The various animal and human genetic material and personae all came bubble to the surface, and when the heroes focused their attacks on him, he exploded. Everyone left after the conclusion of the battle, and "with Prime Evil destroyed the Savage Land is safe once more!" Of course, in the last panel, Prime Evil's hand came bursting from the surface of the waters and the final caption read, "The End?"